JPH0143132B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to intake and exhaust manifolds for four-stroke engines.

(Prior art and its problems) In a conventional four-stroke engine, even if intake and exhaust passages are provided on one side (same side) of the engine, the intake manifold and exhaust manifold connected to the passages are They are formed as separate objects from each other. As a result, the number of parts increases,
The cost is high and assembly work is time consuming.

Furthermore, if the engine configuration requires intake and exhaust passages to be provided in the same direction as described above, it is necessary to provide a gasket containing glass wool, etc., to shield the high pressure in the exhaust pipe. Installation work is time consuming. In addition, the installation space for the intake and exhaust pipes is narrow, making maintenance difficult.

(Means for Solving the Problems) In order to solve the above problems, the present invention integrally molds an intake manifold and an exhaust manifold, opens the intake passage and exhaust passage of the integral molding on the cylinder head side, and between the passage and the exhaust passage.
Forms a cooling water chamber that opens on the cylinder head side,
By attaching the integrally molded product to the cylinder head, the cooling water chamber is completed and communicated with the cooling water chamber within the cylinder head.

(Example) Fig. 1 is a view of an intake and exhaust manifold for a two-cylinder engine to which the present invention is applied, viewed from the cylinder head side. It is integrally molded. The intake manifold 1 includes two left and right intake passages 3, and
An intake source passage 5 is provided in the center. Intake passage 3
is open on the cylinder head side (front side in FIG. 1), the intake source passage 5 is open on the carburetor side (back side in FIG. 1), and both intake passages 3 are in communication with the intake source passage 5.

The exhaust manifold 2 has two exhaust passages 6 on the left and right.
and an exhaust collection passage 7 perpendicular to the exhaust passage 6.
It is equipped with The exhaust passage 6 is parallel to the intake passage 3 and is formed slightly above the intake passage 3, and is arranged to sandwich both the intake passages 3 from the left and right sides. The exhaust gas collection passage 7 is formed above the exhaust gas passage 6 and communicates with the upper surfaces of both exhaust passages 6, and an outlet portion 7a of the exhaust gas collection passage 7 opens at the left end in FIG. Exhaust collection passage 7
A cooling water chamber 11 surrounded by an outer wall 10 is formed around the exhaust passage 6 and the intake passage 3.

The cooling water chamber 11 is open on the cylinder head side, and by attaching the intake and exhaust manifolds 1 and 2 in one piece to the cylinder head, the cooling water chamber 11 can be opened.
communicates with the cooling water chamber in the cylinder head. The end surface of the outer wall 10 on the cylinder head side and the peripheral end surfaces of the intake passage 3 and exhaust passage 6 on the cylinder head side are provided with mating surfaces 10a and 3, respectively.
a, 6a are formed. The intake passages 3 are connected to the intake ports of each cylinder, and the exhaust passages 6 are connected to the exhaust ports of each cylinder.

2 and 3 only show the structure of the intake, intake passages 3, 6, etc. As shown in Figure 2, the intake passage 3
and the exhaust passages 6 are arranged parallel to each other and open in the same direction, the exhaust collecting passage 7 is formed at right angles to the exhaust passage 6 and its left end is open, and the intake source passage 5 is arranged parallel to the intake passage 3. This allows the intake and exhaust manifolds 1 and 2 to be integrally molded by aluminum die casting.

That is, during die casting, the direction in which the cores for the intake and exhaust passages 3 and 6 are removed is in the direction of arrow A, the direction in which the cores for the intake source passage 5 are removed is in the direction of arrow B, and the direction in which the cores are removed for the intake and exhaust passages 7 is in the direction of arrow B. The child removal direction is in the direction of arrow C. Therefore, aluminum die casting allows integral molding.

Also, the direction of removing the core for the cooling water chamber 11 is indicated by arrow A.
direction. Note that the carburetor side (arrow B side) of the exhaust gas collection passage 7 directly becomes the outer wall 10, and therefore the carburetor side (arrow B side) of the exhaust gas collection passage 7.
No cooling water chamber is formed on the surface.

(Another Embodiment) Figures 4, 5, and 6 show examples applied to a three-cylinder engine, and as clearly shown in Figure 6, the intake manifold 1 and the exhaust manifold 2 are formed as one piece. A cooling water chamber 11 is formed between the intake passage 3 and the exhaust passage 6. 12 is an exhaust port, 13 is an exhaust valve, and 14 is a cylinder head. Further, 11a is a cooling water chamber within the cylinder head 14.

As shown in detail in FIG. 5, the structure of the intake manifold 1 in this embodiment is a so-called modified tournament structure with two stages, upper and lower. The length of the intake passage to the end is equal.

That is, the intake source passage 5 is disposed above the intake passage 3, and the two passages 5 and 3 are connected by a bifurcated vertical passage 15 and a horizontal communication passage 16. The intake passages 3 are arranged at equal intervals from each other and communicate with the communication passage 16. The upper end of the vertical passage 15 is connected to the intake source passage 5 at the center of its left and right width, and the lower ends of the vertical passage 15 are connected to the communication passage 1 at the center between each intake passage 3.
It is connected to 6 parts. With the configuration of the modified tournament system as described above, each intake passage length in the intake manifold 1 becomes equal, and the intake speed for each cylinder becomes equal, so that stability of performance of each cylinder can be ensured.

Furthermore, since the intake manifold 1 is constructed in two stages, upper and lower, the amount of overhang of the carburetor from the side of the engine can be reduced, and the overall engine can be made more compact.

Further, as described above, by reducing the amount of overhang of the carburetor from the side of the engine, vibrations of the carburetor can be reduced. As a result, the oil level in the float chamber becomes stable and the performance of the carburetor remains constant.

(Effects of the Invention) As explained above, the present invention has the following advantages: (1) Since the intake manifold and the exhaust manifold are integrally molded, the number of parts for the intake and exhaust manifolds and the number of parts such as bolts for attaching them can be reduced. can be reduced. This makes it possible to reduce the weight and size of the engine, as well as reduce manufacturing costs and facilitate assembly.

In addition, the intake passage and exhaust passage of the integrated molded product are opened on the cylinder head side, and the cooling water chamber is opened on the cylinder head side, and the cooling water chamber is completed by attaching the above integral molded product to the cylinder head. For example, during aluminum die casting molding, the core for the cooling water chamber can be pulled out in the same direction as the core for the suction and exhaust passages, making manufacturing even easier. . Furthermore, since the side surface of the cylinder head can be used as part of the wall surrounding the cooling water chamber, further weight reduction can be achieved.

(2) Since the cooling water chamber is formed between the intake passage and the exhaust passage, the temperature rise in the engine room due to exhaust gas can be efficiently prevented by the cooling water in the cooling water chamber. Furthermore, the intake air temperature can be maintained at a constant value by the temperature of the cooling water in the cooling water chamber, which is heated by the exhaust gas, thereby ensuring stability in engine performance.

(3) Since the cooling water chamber is formed in the integral molding of the intake and exhaust manifolds to shield the temperature of the exhaust passage, the intake and exhaust passages have no choice but to be placed in the same direction due to the structure. In this case, it is no longer necessary to shield the exhaust pipe (exhaust manifold) with a gasket containing glass wool as in the past, and the assembly and maintenance of the intake and exhaust manifolds become easier.

[Brief explanation of drawings]

Figure 1 is a front view of an intake and exhaust manifold to which the present invention is applied, seen from the cylinder head side, Figures 2 and 3 only show the structure of the intake and exhaust passages, and Figure 2 is the same as Figure 1. 3 is a view corresponding to the direction of the arrows in FIG. 2, FIG. 4 is a perspective view showing only the structure of the intake and exhaust passages of another embodiment, and FIG. 5 is a view of the intake manifold portion of FIG. 4. A schematic perspective view, and FIG. 6 is a longitudinal sectional view corresponding to the - section in FIG. 4. 1...Intake manifold, 2...Exhaust manifold, 3...Intake passage, 6...Exhaust passage, 11...Cooling water chamber.

Claims (1)

[Claims] 1. An intake manifold and an exhaust manifold are integrally molded, the cylinder head side of the intake passage and exhaust passage of the integral molding are opened, and a cooling water chamber is formed between the intake passage and the exhaust passage, the cylinder head side being open. An intake/exhaust manifold for a four-stroke engine, characterized in that a cooling water chamber is completed by attaching the integrally molded product to a cylinder head, and the manifold communicates with the cooling water chamber in the cylinder head.